For the manufacture of integrated circuits on silicon wafers, the control and manipulation of the wafers takes place from storage cassettes in which they are positioned horizontally. Each cassette has a series of lateral supports able to horizontally receive the series of wafers having identical dimensions. The handling of the wafers makes it necessary to use a system making it possible to take up a wafer stored in a cassette and then place said wafer in any random cassette at any random stage.
In order to carry out these operations of gripping and putting back into place a wafer with respect to a cassette, it is known to use a gripping mechanism essentially constituted by a gripping finger able to take up a single wafer from the cassette and to put it back into place there. Bearing in mind the very limited height space separating two adjacent wafers, which is only approximately 5 mm for the "semi-engineering" standard, the movements of said gripping finger must be very precise. Thus, any gripping system must be able to penetrate beneath the wafer to be removed without scratching the upper wafer. The height positioning of the gripping finger is ensured by a very precise, but onerous mechanical device, which brings about the vertical translation of the finger and its support. The gripping finger can also remain fixed, the precise vertical translation movement then being ensured by another mechanical device moving the cassette. In the latter case, it is the precision of the cassette translation mechanism which is very costly.
A first aim of the invention is to provide an apparatus for gripping and releasing the wafer with respect to a cassette, which must be very slender, i.e. it must be able to penetrate between the racks of the cassette without any difficulty. In addition, it must be easy to manipulate and of reduced cost compared with the aforementioned gripping means.